A typical bearing assembly for a slotted tube shaft of a head of a bandsaw-blade twister is rotatably mounted in a slotted, stationary bearing housing for an endless, self-contained, band-shaped cutting or sawing element, typically a bandsaw blade. Such bearing assemblies are used for contour or shape-cutting machines with blade twisters that are rotated to align the blade in the cutting direction.
In endless welded bandsaw blades of contour-cutting machines, the blade must be moved along the axis of rotation of the blade twister for cutting. This is only possible if, for example, the blade is threaded through the twisters, then welded in the machine or, alternatively, if the blade twister that positions the blade in the cutting direction has a mounting opening, for example a slot allowing the blade to be moved perpendicular to the twist axis into the blade twister.
It is generally known to allow the tube shaft to rotate in a slide bearing as a simple construction within a bearing housing. Drawbacks of the slide bearing are the different thermal expansion values of metal and plastic, sliding friction with a high stick-slip effect, and the danger of contamination.
U.S. Pat. No. 6,868,765 describes a shape-cutting machine, particularly for foam, with a workpiece table having a transverse table gap and a drive for moving workpieces longitudinally past the table gap. The workpieces are cut using an endless cutting element, for example an endless bandsaw blade that passes through the table gap, is tensioned by wheels, and can be driven in the vertical direction through a cutting area by a drive. In order to enable different contour cuts to be executed using an endless blade, the blade must be twisted in the cutting area according to the desired curve, and a blade twister is provided for this purpose that has two blade heads. The blade is guided through the blade heads such that the cutting edge of the blade passes precisely through the axis of rotation of the two blade heads.
EP 0 738 569 B1 describes a vertical contour cutting machine with two blade twisters for rotating a blade and that are each provided with drivable, slotted tube shafts and blade guides each having two guide rollers and a brace roller as well as a scraper. The slots allow the endless welded blade to be easily introduced laterally to a position extending along the axis of rotation of the blade twister. The tube shaft is held in a housing against radial and axial displacements by rollers for supporting and bracing the tube shaft.